Boilers, the most troublesome components of electric power generation plants cost US utility industry over $5 billion per year in unscheduled shutdowns, repairs and power replacement. The nondestructive testing technique is an important tool to predict the life of boiler tubes. Standard ultrasonic technique is used for measuring wall thickness and determining the degree of corrosion. Such test requires clean, rust-free surface and all tubes must be sandblasted and cleaned prior to the inspection. This adds precious hours to boiler outage time. The paper presents the application of EMAT (Electromagnetic-Acoustic Transducer) that accurately measures tube wall thickness through thick layers of crusty scale -the kind most often found in aging fossil fired boilers. Numerous field trials were carried out during last outage season. Back-to-back tests showed good agreement between the EMAT technique and classic D-meter thickness gauge. It was concluded that EMAT provides accurate data and therefore offers an attractive possibility for significant cost cutting in the electric power generation industry. During last few months, the described EMAT technology became widely accepted and used throughout the world. Many successful boiler examinations were conducted in USA, UK, Japan, South Africa and other countries.
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